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Added in API level 11

ValueAnimator

public class ValueAnimator
extends Animator

java.lang.Object
   ↳ android.animation.Animator
     ↳ android.animation.ValueAnimator
Known Direct Subclasses


This class provides a simple timing engine for running animations which calculate animated values and set them on target objects.

There is a single timing pulse that all animations use. It runs in a custom handler to ensure that property changes happen on the UI thread.

By default, ValueAnimator uses non-linear time interpolation, via the AccelerateDecelerateInterpolator class, which accelerates into and decelerates out of an animation. This behavior can be changed by calling setInterpolator(TimeInterpolator).

Animators can be created from either code or resource files. Here is an example of a ValueAnimator resource file:

<animator xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="1000"
    android:valueFrom="1"
    android:valueTo="0"
    android:valueType="floatType"
    android:repeatCount="1"
    android:repeatMode="reverse"/>

It is also possible to use a combination of PropertyValuesHolder and Keyframe resource tags to create a multi-step animation. Note that you can specify explicit fractional values (from 0 to 1) for each keyframe to determine when, in the overall duration, the animation should arrive at that value. Alternatively, you can leave the fractions off and the keyframes will be equally distributed within the total duration:

<animator xmlns:android="http://schemas.android.com/apk/res/android"
          android:duration="1000"
          android:repeatCount="1"
          android:repeatMode="reverse">
    <propertyValuesHolder>
        <keyframe android:fraction="0" android:value="1"/>
        <keyframe android:fraction=".2" android:value=".4"/>
        <keyframe android:fraction="1" android:value="0"/>
    </propertyValuesHolder>
</animator>

Developer Guides

For more information about animating with ValueAnimator, read the Property Animation developer guide.

Summary

Nested classes

interface ValueAnimator.AnimatorUpdateListener

Implementors of this interface can add themselves as update listeners to an ValueAnimator instance to receive callbacks on every animation frame, after the current frame's values have been calculated for that ValueAnimator

Constants

int INFINITE

This value used used with the setRepeatCount(int) property to repeat the animation indefinitely.

int RESTART

When the animation reaches the end and repeatCount is INFINITE or a positive value, the animation restarts from the beginning.

int REVERSE

When the animation reaches the end and repeatCount is INFINITE or a positive value, the animation reverses direction on every iteration.

Public constructors

ValueAnimator()

Creates a new ValueAnimator object.

Public methods

void addUpdateListener(ValueAnimator.AnimatorUpdateListener listener)

Adds a listener to the set of listeners that are sent update events through the life of an animation.

void cancel()

Cancels the animation.

ValueAnimator clone()

Creates and returns a copy of this Object.

void end()

Ends the animation.

float getAnimatedFraction()

Returns the current animation fraction, which is the elapsed/interpolated fraction used in the most recent frame update on the animation.

Object getAnimatedValue()

The most recent value calculated by this ValueAnimator when there is just one property being animated.

Object getAnimatedValue(String propertyName)

The most recent value calculated by this ValueAnimator for propertyName.

long getCurrentPlayTime()

Gets the current position of the animation in time, which is equal to the current time minus the time that the animation started.

long getDuration()

Gets the length of the animation.

static long getFrameDelay()

The amount of time, in milliseconds, between each frame of the animation.

TimeInterpolator getInterpolator()

Returns the timing interpolator that this ValueAnimator uses.

int getRepeatCount()

Defines how many times the animation should repeat.

int getRepeatMode()

Defines what this animation should do when it reaches the end.

long getStartDelay()

The amount of time, in milliseconds, to delay starting the animation after start() is called.

PropertyValuesHolder[] getValues()

Returns the values that this ValueAnimator animates between.

boolean isRunning()

Returns whether this Animator is currently running (having been started and gone past any initial startDelay period and not yet ended).

boolean isStarted()

Returns whether this Animator has been started and not yet ended.

static ValueAnimator ofArgb(int... values)

Constructs and returns a ValueAnimator that animates between color values.

static ValueAnimator ofFloat(float... values)

Constructs and returns a ValueAnimator that animates between float values.

static ValueAnimator ofInt(int... values)

Constructs and returns a ValueAnimator that animates between int values.

static ValueAnimator ofObject(TypeEvaluator evaluator, Object... values)

Constructs and returns a ValueAnimator that animates between Object values.

static ValueAnimator ofPropertyValuesHolder(PropertyValuesHolder... values)

Constructs and returns a ValueAnimator that animates between the values specified in the PropertyValuesHolder objects.

void pause()

Pauses a running animation.

void removeAllUpdateListeners()

Removes all listeners from the set listening to frame updates for this animation.

void removeUpdateListener(ValueAnimator.AnimatorUpdateListener listener)

Removes a listener from the set listening to frame updates for this animation.

void resume()

Resumes a paused animation, causing the animator to pick up where it left off when it was paused.

void reverse()

Plays the ValueAnimator in reverse.

void setCurrentFraction(float fraction)

Sets the position of the animation to the specified fraction.

void setCurrentPlayTime(long playTime)

Sets the position of the animation to the specified point in time.

ValueAnimator setDuration(long duration)

Sets the length of the animation.

void setEvaluator(TypeEvaluator value)

The type evaluator to be used when calculating the animated values of this animation.

void setFloatValues(float... values)

Sets float values that will be animated between.

static void setFrameDelay(long frameDelay)

The amount of time, in milliseconds, between each frame of the animation.

void setIntValues(int... values)

Sets int values that will be animated between.

void setInterpolator(TimeInterpolator value)

The time interpolator used in calculating the elapsed fraction of this animation.

void setObjectValues(Object... values)

Sets the values to animate between for this animation.

void setRepeatCount(int value)

Sets how many times the animation should be repeated.

void setRepeatMode(int value)

Defines what this animation should do when it reaches the end.

void setStartDelay(long startDelay)

The amount of time, in milliseconds, to delay starting the animation after start() is called.

void setValues(PropertyValuesHolder... values)

Sets the values, per property, being animated between.

void start()

Starts this animation.

String toString()

Returns a string containing a concise, human-readable description of this object.

Inherited methods

From class android.animation.Animator
From class java.lang.Object

Constants

INFINITE

Added in API level 11
int INFINITE

This value used used with the setRepeatCount(int) property to repeat the animation indefinitely.

Constant Value: -1 (0xffffffff)

RESTART

Added in API level 11
int RESTART

When the animation reaches the end and repeatCount is INFINITE or a positive value, the animation restarts from the beginning.

Constant Value: 1 (0x00000001)

REVERSE

Added in API level 11
int REVERSE

When the animation reaches the end and repeatCount is INFINITE or a positive value, the animation reverses direction on every iteration.

Constant Value: 2 (0x00000002)

Public constructors

ValueAnimator

Added in API level 11
ValueAnimator ()

Creates a new ValueAnimator object. This default constructor is primarily for use internally; the factory methods which take parameters are more generally useful.

Public methods

addUpdateListener

Added in API level 11
void addUpdateListener (ValueAnimator.AnimatorUpdateListener listener)

Adds a listener to the set of listeners that are sent update events through the life of an animation. This method is called on all listeners for every frame of the animation, after the values for the animation have been calculated.

Parameters
listener ValueAnimator.AnimatorUpdateListener: the listener to be added to the current set of listeners for this animation.

cancel

Added in API level 11
void cancel ()

Cancels the animation. Unlike end(), cancel() causes the animation to stop in its tracks, sending an onAnimationCancel(Animator) to its listeners, followed by an onAnimationEnd(Animator) message.

This method must be called on the thread that is running the animation.

clone

Added in API level 11
ValueAnimator clone ()

Creates and returns a copy of this Object. The default implementation returns a so-called "shallow" copy: It creates a new instance of the same class and then copies the field values (including object references) from this instance to the new instance. A "deep" copy, in contrast, would also recursively clone nested objects. A subclass that needs to implement this kind of cloning should call super.clone() to create the new instance and then create deep copies of the nested, mutable objects.

Returns
ValueAnimator a copy of this object.

end

Added in API level 11
void end ()

Ends the animation. This causes the animation to assign the end value of the property being animated, then calling the onAnimationEnd(Animator) method on its listeners.

This method must be called on the thread that is running the animation.

getAnimatedFraction

Added in API level 12
float getAnimatedFraction ()

Returns the current animation fraction, which is the elapsed/interpolated fraction used in the most recent frame update on the animation.

Returns
float Elapsed/interpolated fraction of the animation.

getAnimatedValue

Added in API level 11
Object getAnimatedValue ()

The most recent value calculated by this ValueAnimator when there is just one property being animated. This value is only sensible while the animation is running. The main purpose for this read-only property is to retrieve the value from the ValueAnimator during a call to onAnimationUpdate(ValueAnimator), which is called during each animation frame, immediately after the value is calculated.

Returns
Object animatedValue The value most recently calculated by this ValueAnimator for the single property being animated. If there are several properties being animated (specified by several PropertyValuesHolder objects in the constructor), this function returns the animated value for the first of those objects.

getAnimatedValue

Added in API level 11
Object getAnimatedValue (String propertyName)

The most recent value calculated by this ValueAnimator for propertyName. The main purpose for this read-only property is to retrieve the value from the ValueAnimator during a call to onAnimationUpdate(ValueAnimator), which is called during each animation frame, immediately after the value is calculated.

Parameters
propertyName String
Returns
Object animatedValue The value most recently calculated for the named property by this ValueAnimator.

getCurrentPlayTime

Added in API level 11
long getCurrentPlayTime ()

Gets the current position of the animation in time, which is equal to the current time minus the time that the animation started. An animation that is not yet started will return a value of zero.

Returns
long The current position in time of the animation.

getDuration

Added in API level 11
long getDuration ()

Gets the length of the animation. The default duration is 300 milliseconds.

Returns
long The length of the animation, in milliseconds.

getFrameDelay

Added in API level 11
long getFrameDelay ()

The amount of time, in milliseconds, between each frame of the animation. This is a requested time that the animation will attempt to honor, but the actual delay between frames may be different, depending on system load and capabilities. This is a static function because the same delay will be applied to all animations, since they are all run off of a single timing loop. The frame delay may be ignored when the animation system uses an external timing source, such as the display refresh rate (vsync), to govern animations.

Returns
long the requested time between frames, in milliseconds

getInterpolator

Added in API level 11
TimeInterpolator getInterpolator ()

Returns the timing interpolator that this ValueAnimator uses.

Returns
TimeInterpolator The timing interpolator for this ValueAnimator.

getRepeatCount

Added in API level 11
int getRepeatCount ()

Defines how many times the animation should repeat. The default value is 0.

Returns
int the number of times the animation should repeat, or INFINITE

getRepeatMode

Added in API level 11
int getRepeatMode ()

Defines what this animation should do when it reaches the end.

Returns
int either one of REVERSE or RESTART

getStartDelay

Added in API level 11
long getStartDelay ()

The amount of time, in milliseconds, to delay starting the animation after start() is called.

Returns
long the number of milliseconds to delay running the animation

getValues

Added in API level 11
PropertyValuesHolder[] getValues ()

Returns the values that this ValueAnimator animates between. These values are stored in PropertyValuesHolder objects, even if the ValueAnimator was created with a simple list of value objects instead.

Returns
PropertyValuesHolder[] PropertyValuesHolder[] An array of PropertyValuesHolder objects which hold the values, per property, that define the animation.

isRunning

Added in API level 11
boolean isRunning ()

Returns whether this Animator is currently running (having been started and gone past any initial startDelay period and not yet ended).

Returns
boolean Whether the Animator is running.

isStarted

Added in API level 14
boolean isStarted ()

Returns whether this Animator has been started and not yet ended. For reusable Animators (which most Animators are, apart from the one-shot animator produced by createCircularReveal()), this state is a superset of isRunning(), because an Animator with a nonzero startDelay will return true for isStarted() during the delay phase, whereas isRunning() will return true only after the delay phase is complete. Non-reusable animators will always return true after they have been started, because they cannot return to a non-started state.

Returns
boolean Whether the Animator has been started and not yet ended.

ofArgb

Added in API level 21
ValueAnimator ofArgb (int... values)

Constructs and returns a ValueAnimator that animates between color values. A single value implies that that value is the one being animated to. However, this is not typically useful in a ValueAnimator object because there is no way for the object to determine the starting value for the animation (unlike ObjectAnimator, which can derive that value from the target object and property being animated). Therefore, there should typically be two or more values.

Parameters
values int: A set of values that the animation will animate between over time.
Returns
ValueAnimator A ValueAnimator object that is set up to animate between the given values.

ofFloat

Added in API level 11
ValueAnimator ofFloat (float... values)

Constructs and returns a ValueAnimator that animates between float values. A single value implies that that value is the one being animated to. However, this is not typically useful in a ValueAnimator object because there is no way for the object to determine the starting value for the animation (unlike ObjectAnimator, which can derive that value from the target object and property being animated). Therefore, there should typically be two or more values.

Parameters
values float: A set of values that the animation will animate between over time.
Returns
ValueAnimator A ValueAnimator object that is set up to animate between the given values.

ofInt

Added in API level 11
ValueAnimator ofInt (int... values)

Constructs and returns a ValueAnimator that animates between int values. A single value implies that that value is the one being animated to. However, this is not typically useful in a ValueAnimator object because there is no way for the object to determine the starting value for the animation (unlike ObjectAnimator, which can derive that value from the target object and property being animated). Therefore, there should typically be two or more values.

Parameters
values int: A set of values that the animation will animate between over time.
Returns
ValueAnimator A ValueAnimator object that is set up to animate between the given values.

ofObject

Added in API level 11
ValueAnimator ofObject (TypeEvaluator evaluator, 
                Object... values)

Constructs and returns a ValueAnimator that animates between Object values. A single value implies that that value is the one being animated to. However, this is not typically useful in a ValueAnimator object because there is no way for the object to determine the starting value for the animation (unlike ObjectAnimator, which can derive that value from the target object and property being animated). Therefore, there should typically be two or more values.

Since ValueAnimator does not know how to animate between arbitrary Objects, this factory method also takes a TypeEvaluator object that the ValueAnimator will use to perform that interpolation.

Parameters
evaluator TypeEvaluator: A TypeEvaluator that will be called on each animation frame to provide the ncessry interpolation between the Object values to derive the animated value.
values Object: A set of values that the animation will animate between over time.
Returns
ValueAnimator A ValueAnimator object that is set up to animate between the given values.

ofPropertyValuesHolder

Added in API level 11
ValueAnimator ofPropertyValuesHolder (PropertyValuesHolder... values)

Constructs and returns a ValueAnimator that animates between the values specified in the PropertyValuesHolder objects.

Parameters
values PropertyValuesHolder: A set of PropertyValuesHolder objects whose values will be animated between over time.
Returns
ValueAnimator A ValueAnimator object that is set up to animate between the given values.

pause

Added in API level 19
void pause ()

Pauses a running animation. This method should only be called on the same thread on which the animation was started. If the animation has not yet been started or has since ended, then the call is ignored. Paused animations can be resumed by calling resume().

removeAllUpdateListeners

Added in API level 11
void removeAllUpdateListeners ()

Removes all listeners from the set listening to frame updates for this animation.

removeUpdateListener

Added in API level 11
void removeUpdateListener (ValueAnimator.AnimatorUpdateListener listener)

Removes a listener from the set listening to frame updates for this animation.

Parameters
listener ValueAnimator.AnimatorUpdateListener: the listener to be removed from the current set of update listeners for this animation.

resume

Added in API level 19
void resume ()

Resumes a paused animation, causing the animator to pick up where it left off when it was paused. This method should only be called on the same thread on which the animation was started. Calls to resume() on an animator that is not currently paused will be ignored.

reverse

Added in API level 11
void reverse ()

Plays the ValueAnimator in reverse. If the animation is already running, it will stop itself and play backwards from the point reached when reverse was called. If the animation is not currently running, then it will start from the end and play backwards. This behavior is only set for the current animation; future playing of the animation will use the default behavior of playing forward.

setCurrentFraction

Added in API level 22
void setCurrentFraction (float fraction)

Sets the position of the animation to the specified fraction. This fraction should be between 0 and the total fraction of the animation, including any repetition. That is, a fraction of 0 will position the animation at the beginning, a value of 1 at the end, and a value of 2 at the end of a reversing animator that repeats once. If the animation has not yet been started, then it will not advance forward after it is set to this fraction; it will simply set the fraction to this value and perform any appropriate actions based on that fraction. If the animation is already running, then setCurrentFraction() will set the current fraction to this value and continue playing from that point. Animator.AnimatorListener events are not called due to changing the fraction; those events are only processed while the animation is running.

Parameters
fraction float: The fraction to which the animation is advanced or rewound. Values outside the range of 0 to the maximum fraction for the animator will be clamped to the correct range.

setCurrentPlayTime

Added in API level 11
void setCurrentPlayTime (long playTime)

Sets the position of the animation to the specified point in time. This time should be between 0 and the total duration of the animation, including any repetition. If the animation has not yet been started, then it will not advance forward after it is set to this time; it will simply set the time to this value and perform any appropriate actions based on that time. If the animation is already running, then setCurrentPlayTime() will set the current playing time to this value and continue playing from that point.

Parameters
playTime long: The time, in milliseconds, to which the animation is advanced or rewound.

setDuration

Added in API level 11
ValueAnimator setDuration (long duration)

Sets the length of the animation. The default duration is 300 milliseconds.

Parameters
duration long: The length of the animation, in milliseconds. This value cannot be negative.
Returns
ValueAnimator ValueAnimator The object called with setDuration(). This return value makes it easier to compose statements together that construct and then set the duration, as in ValueAnimator.ofInt(0, 10).setDuration(500).start().

setEvaluator

Added in API level 11
void setEvaluator (TypeEvaluator value)

The type evaluator to be used when calculating the animated values of this animation. The system will automatically assign a float or int evaluator based on the type of startValue and endValue in the constructor. But if these values are not one of these primitive types, or if different evaluation is desired (such as is necessary with int values that represent colors), a custom evaluator needs to be assigned. For example, when running an animation on color values, the ArgbEvaluator should be used to get correct RGB color interpolation.

If this ValueAnimator has only one set of values being animated between, this evaluator will be used for that set. If there are several sets of values being animated, which is the case if PropertyValuesHolder objects were set on the ValueAnimator, then the evaluator is assigned just to the first PropertyValuesHolder object.

Parameters
value TypeEvaluator: the evaluator to be used this animation

setFloatValues

Added in API level 11
void setFloatValues (float... values)

Sets float values that will be animated between. A single value implies that that value is the one being animated to. However, this is not typically useful in a ValueAnimator object because there is no way for the object to determine the starting value for the animation (unlike ObjectAnimator, which can derive that value from the target object and property being animated). Therefore, there should typically be two or more values.

If there are already multiple sets of values defined for this ValueAnimator via more than one PropertyValuesHolder object, this method will set the values for the first of those objects.

Parameters
values float: A set of values that the animation will animate between over time.

setFrameDelay

Added in API level 11
void setFrameDelay (long frameDelay)

The amount of time, in milliseconds, between each frame of the animation. This is a requested time that the animation will attempt to honor, but the actual delay between frames may be different, depending on system load and capabilities. This is a static function because the same delay will be applied to all animations, since they are all run off of a single timing loop. The frame delay may be ignored when the animation system uses an external timing source, such as the display refresh rate (vsync), to govern animations.

Parameters
frameDelay long: the requested time between frames, in milliseconds

setIntValues

Added in API level 11
void setIntValues (int... values)

Sets int values that will be animated between. A single value implies that that value is the one being animated to. However, this is not typically useful in a ValueAnimator object because there is no way for the object to determine the starting value for the animation (unlike ObjectAnimator, which can derive that value from the target object and property being animated). Therefore, there should typically be two or more values.

If there are already multiple sets of values defined for this ValueAnimator via more than one PropertyValuesHolder object, this method will set the values for the first of those objects.

Parameters
values int: A set of values that the animation will animate between over time.

setInterpolator

Added in API level 11
void setInterpolator (TimeInterpolator value)

The time interpolator used in calculating the elapsed fraction of this animation. The interpolator determines whether the animation runs with linear or non-linear motion, such as acceleration and deceleration. The default value is AccelerateDecelerateInterpolator

Parameters
value TimeInterpolator: the interpolator to be used by this animation. A value of null will result in linear interpolation.

setObjectValues

Added in API level 11
void setObjectValues (Object... values)

Sets the values to animate between for this animation. A single value implies that that value is the one being animated to. However, this is not typically useful in a ValueAnimator object because there is no way for the object to determine the starting value for the animation (unlike ObjectAnimator, which can derive that value from the target object and property being animated). Therefore, there should typically be two or more values.

If there are already multiple sets of values defined for this ValueAnimator via more than one PropertyValuesHolder object, this method will set the values for the first of those objects.

There should be a TypeEvaluator set on the ValueAnimator that knows how to interpolate between these value objects. ValueAnimator only knows how to interpolate between the primitive types specified in the other setValues() methods.

Parameters
values Object: The set of values to animate between.

setRepeatCount

Added in API level 11
void setRepeatCount (int value)

Sets how many times the animation should be repeated. If the repeat count is 0, the animation is never repeated. If the repeat count is greater than 0 or INFINITE, the repeat mode will be taken into account. The repeat count is 0 by default.

Parameters
value int: the number of times the animation should be repeated

setRepeatMode

Added in API level 11
void setRepeatMode (int value)

Defines what this animation should do when it reaches the end. This setting is applied only when the repeat count is either greater than 0 or INFINITE. Defaults to RESTART.

Parameters
value int: RESTART or REVERSE

setStartDelay

Added in API level 11
void setStartDelay (long startDelay)

The amount of time, in milliseconds, to delay starting the animation after start() is called.

Parameters
startDelay long: The amount of the delay, in milliseconds

setValues

Added in API level 11
void setValues (PropertyValuesHolder... values)

Sets the values, per property, being animated between. This function is called internally by the constructors of ValueAnimator that take a list of values. But a ValueAnimator can be constructed without values and this method can be called to set the values manually instead.

Parameters
values PropertyValuesHolder: The set of values, per property, being animated between.

start

Added in API level 11
void start ()

Starts this animation. If the animation has a nonzero startDelay, the animation will start running after that delay elapses. A non-delayed animation will have its initial value(s) set immediately, followed by calls to onAnimationStart(Animator) for any listeners of this animator.

The animation started by calling this method will be run on the thread that called this method. This thread should have a Looper on it (a runtime exception will be thrown if this is not the case). Also, if the animation will animate properties of objects in the view hierarchy, then the calling thread should be the UI thread for that view hierarchy.

toString

Added in API level 11
String toString ()

Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression:

   getClass().getName() + '@' + Integer.toHexString(hashCode())

See Writing a useful toString method if you intend implementing your own toString method.

Returns
String a printable representation of this object.
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